Dermatology Flashcards
Causes of acanthosis nigricans
type 2 diabetes mellitus
Addisons disease
gastrointestinal cancer
obesity
polycystic ovarian syndrome
acromegaly
Cushing’s disease
hypothyroidism
familial
Prader-Willi syndrome
drugs- combined oral contraceptive pill, nicotinic acid
Typical features of acne vulgaris
Comedones are due to a dilated sebaceous follicle
-if the top is closed a whitehead is seen
-if the top opens a blackhead forms
Inflammatory changes seen in acne vulgaris
papules
pustules
An excessive inflammatory response may result in:
nodules
cysts
NB- eventually scars may form eg. ice pick scars, hypertrophic scars
Management of acne vulgaris
Mild- benzoyl peroxide, topical antibiotics, and topical retinoids
Moderate- oral antibiotics, and anti-androgens (in females) eg. COCT (Dianette- risk of VTE)
Severe- oral retinoids (eg. isoretinoin)
NB- ABX of choice: tetracyclines: lymecycline, oxytetracycline, doxycycline (erythromycin in pregnancy, breastfeeding, children under 12)
NB- pregnancy is contraindicated to oral or topical retinoids
Actinic keratoses
Pre-malignant skin lesions that form as a result of chronic sun exposure;
small, crusty or scaly, lesions
may be pink, red, brown or the same colour as the skin
typically on sun-exposed areas e.g. temples of head
multiple lesions may be present
Management of actinic keratoses
Lifestyle- sun avoidance, sun cream
Medical- fluorouracil cream (sometimes topical hydrocortisone is given following fluorouracil to help settle the inflammation), topical diclofenac, topical imiquimod, cryotherapy
Surgery- curettage and cautery
BCC
Most common cancer in the Western world
many types of BCC are described. The most common type is nodular BCC, which is described here
sun-exposed sites, especially the head and neck account for the majority of lesions
initially a pearly, flesh-coloured papule with telangiectasia
may later ulcerate leaving a central ‘crater’
Management;
surgical removal
curettage
cryotherapy
topical cream: imiquimod, fluorouracil
radiotherapy
Bowens disease
Bowen’s disease is a type of precancerous dermatosis that is a precursor to squamous cell carcinoma. It is more common in elderly patients. There is around a 5-10% chance of developing invasive skin cancer if left untreated.
red, scaly patches
often 10-15 mm in size
slow-growing
often occur on sun-exposed areas such as the head (e.g. temples) and neck, lower limbs
Management of Bowens disease
-may sometimes be diagnosed and managed in primary care if clear diagnosis or repeat episode
-topical 5-fluorouracil (typically used twice daily for 4 weeks, often results in significant inflammation/erythema. Topical steroids are often given to control this)
-cryotherapy
-excision
Bullous Pemphigoid
An autoimmune condition causing sub-epidermal blistering of the skin.
itchy, tense blisters typically around flexures
the blisters usually heal without scarring
there is usually no mucosal involvement (i.e. the mouth is spared)*
investigation- immunofluorescence shows IgG and C3 at the dermoepidermal junction
Management- refer to dermatology, oral steroids and immunosuppressants, also oral steroids and ABX
Assessing extent of a burn
Lund and Browder chart: the most accurate method
Which burns are referred to secondary care
all deep dermal and full-thickness burns.
superficial dermal burns of more than 3% TBSA in adults, or more than 2% TBSA in children
superficial dermal burns involving the face, hands, feet, perineum, genitalia, or any flexure, or circumferential burns of the limbs, torso, or neck
any inhalation injury
any electrical or chemical burn injury
suspicion of non-accidental injury
Initial burn management
superficial epidermal: symptomatic relief - analgesia, emollients etc
superficial dermal: cleanse wound, leave blister intact, non-adherent dressing, avoid topical creams, review in 24 hours
severe/full thickness: IV fluids, stabilise airway, escharotomy/plastics input
Cherry haemangioma
erythematous, papular lesions
typically 1-3 mm in size
non-blanching
not found on the mucous membranes
Chronic plaque psoriasis
Chronic plaque psoriasis is the most common form of psoriasis seen in clinical practice, accounting for around 80% of presentations.
erythematous plaques covered with a silvery-white scale
typically on the extensor surfaces such as the elbows and knees. Also common on the scalp, trunk, buttocks and periumbilical area
clear delineation between normal and affected skin
plaques typically range from 1 to 10 cm in size
if the scale is removed, a red membrane with pinpoint bleeding points may be seen (Auspitz’s sign)
50% have associated nail changes (e.g. pitting, onycholysis)
Contact dermatitis
irritant contact dermatitis: common - non-allergic reaction due to weak acids or alkalis (e.g. detergents). Often seen on the hands. Erythema is typical, crusting and vesicles are rare
allergic contact dermatitis: type IV hypersensitivity reaction. Uncommon - often seen on the head following hair dyes. Presents as an acute weeping eczema which predominately affects the margins of the hairline rather than the hairy scalp itself. Topical treatment with a potent steroid is indicated
Dermatitis herpetiformis
An autoimmune blistering skin disorder associated with coeliac disease. It is caused by deposition of IgA in the dermis.
Features- itchy, vesicular skin lesions on the extensor surfaces (e.g. elbows, knees, buttocks) and abdomen
Diagnosis- skin biopsy: direct immunofluorescence shows deposition of IgA in a granular pattern in the upper dermis
Management
-gluten-free diet
-dapsone
Deramtofibroma
solitary firm papule or nodule, typically on a limb
typically around 5-10mm in size
overlying skin dimples on pinching the lesion
Eczema herpeticum
Eczema herpeticum describes a severe primary infection of the skin by herpes simplex virus 1 or 2.
It is more commonly seen in children with atopic eczema and often presents as a rapidly progressing painful rash.
On examination, monomorphic punched-out erosions (circular, depressed, ulcerated lesions) usually 1–3 mm in diameter are typically seen. May have itchy vesicles that contain pus. May have lymphadenopathy
As it is potentially life-threatening children should be admitted for IV aciclovir.
Erysipelas
Erysipelas is localised skin infection caused by Streptococcus pyogenes. In simple terms, it is a more superficial, limited version of cellulitis.
The treatment of choice is flucloxacillin.
Erythema ab igne
Erythema ab igne is a skin disorder caused by over exposure to infrared radiation. Characteristic features include reticulated, erythematous patches with hyperpigmentation and telangiectasia. A typical history would be an elderly women who always sits next to an open fire.
If the cause is not treated then patients may go on to develop squamous cell skin cancer.
Erythema multiforme
a hypersensitivity reaction which is most commonly triggered by infections. It may be divided into minor and major forms.
Causes;
viruses: herpes simplex virus (the most common cause), Orf
idiopathic
bacteria: Mycoplasma, Streptococcus
drugs: penicillin, sulphonamides, carbamazepine, allopurinol, NSAIDs, oral contraceptive pill, nevirapine
connective tissue disease e.g. Systemic lupus erythematosus
sarcoidosis
malignancy
Features of erythema multiforme
target lesions
initially seen on the back of the hands / feet before spreading to the torso
upper limbs are more commonly affected than the lower limbs
pruritus is occasionally seen and is usually mild
NB- the more severe form, erythema multiforme major is associated with mucosal involvement.
Erythema nodosum
inflammation of subcutaneous fat
typically causes tender, erythematous, nodular lesions
usually occurs over shins, may also occur elsewhere (e.g. forearms, thighs)
usually resolves within 6 weeks
lesions heal without scarring
Causes of erythema nodusum
infection
-streptococci
-tuberculosis
-brucellosis
systemic disease
-sarcoidosis (with raised calcium)
-inflammatory bowel disease
-Behcet’s
malignancy/lymphoma
drugs
-penicillins
-sulphonamides
-combined oral contraceptive pill
pregnancy
NB- IBD and sarcoid most common
Erythrasma
Erythrasma is a generally asymptomatic, flat, slightly scaly, pink or brown rash usually found in the groin or axillae. It is caused by an overgrowth of the diphtheroid Corynebacterium minutissimum
Examination with Wood’s light reveals a coral-red fluorescence.
Topical miconazole or antibacterial are usually effective. Oral erythromycin may be used for more extensive infection
Erythroderma
Erythroderma is a term used when more than 95% of the skin is involved in a rash of any kind.
Causes of erythroderma;
eczema
psoriasis
drugs e.g. gold
lymphomas, leukaemias
idiopathic
Erythrodermic psoriasis
may result from progression of chronic disease to an exfoliative phase with plaques covering most of the body. Associated with mild systemic upset
more serious form is an acute deterioration. This may be triggered by a variety of factors such as withdrawal of systemic steroids. Patients need to be admitted to hospital for management
Guttate psoriasis
Guttate psoriasis is more common in children and adolescents. It may be precipitated by a streptococcal infection 2-4 weeks prior to the lesions appearing.
Features;
tear drop papules on the trunk and limbs
gutta is Latin for drop
pink, scaly patches or plques of psoriasis
tends to be acute onset over days
Management of guttate psoriasis
most cases resolve spontaneously within 2-3 months
there is no firm evidence to support the use of antibiotics to eradicate streptococcal infection
topical agents as per psoriasis
UVB phototherapy
tonsillectomy may be necessary with recurrent episodes
Onychomycosis
fungal infection of the nails
Risk factors include for fungal nail infections include diabetes mellitus and increasing age.
Features
-‘unsightly’ nails are a common reason for presentation
-thickened, rough, opaque nails are the most common finding
Differential diagnosis;
psoriasis
repeated trauma
lichen planus
yellow nail syndrome
Investigation;
nail clippings
scrapings of the affected nail
Management of fungal nail infections
Asymptomatic and not bothered- no treatment
dermatophyte infection (Trichophyton rubrum)- oral terbinafine is currently recommended first-line with oral itraconazole as an alternative. 6 weeks - 3 months therapy is needed for fingernail infections whilst toenails should be treated for 3 - 6 months. treatment is successful in around 50-80% of people
Candida infection- mild disease should be treated with topical antifungals (e.g. Amorolfine) whilst more severe infections should be treated with oral itraconazole for a period of 12 weeks
NB- ine’s are first line, oral itraconazole second line
NB- T for T, terbinafine for trichophyton
HHT
an autosomal dominant condition characterised by (as the name suggests) multiple telangiectasia over the skin and mucous membranes. Twenty percent of cases occur spontaneously without prior family history.
epistaxis : spontaneous, recurrent nosebleeds
telangiectases: multiple at characteristic sites (lips, oral cavity, fingers, nose)
visceral lesions: for example gastrointestinal telangiectasia (with or without bleeding), pulmonary arteriovenous malformations (AVM), hepatic AVM, cerebral AVM, spinal AVM
NB- usually have a positive FH
Hidradenitis suppurativa
a chronic, painful, inflammatory skin disorder. It is characterized by the development of inflammatory nodules, pustules, sinus tracts, and scars in intertriginous areas. It should be suspected in pubertal or post-pubertal patients who have a diagnosis of recurrent furuncles or boils, especially in intertriginous areas.
Management of Hidradenitis suppurativa
Lifestyle- Encourage good hygiene and loose-fitting clothing, Smoking cessation, Weight loss in obese
Acute flares can be treated with steroids (intra-lesional or oral) or flucloxacillin. Surgical incision and drainage may be needed in some cases.
Long-term disease can be treated with topical (clindamycin) or oral (lymecycline or clindamycin and rifampicin) antibiotics.
Lumps that persist despite prolonged medical treatment are excised surgically.
Hirsutism (women)
androgen-dependent hair growth in women (ie. specific to androgenous regions ie. face, chin, axillae, pubis etc.)
Polycystic ovarian syndrome
Cushing’s syndrome
congenital adrenal hyperplasia
androgen therapy
obesity: thought to be due to insulin resistance
adrenal tumour
androgen secreting ovarian tumour
drugs: phenytoin, corticosteroids
Hypertrichosis (women and men)
androgen-independent hair growth (ie. not specific to androgenous regions ie. whole body)
drugs: minoxidil, ciclosporin, diazoxide
congenital hypertrichosis lanuginosa, congenital hypertrichosis terminalis
porphyria cutanea tarda
anorexia nervosa
Management of hirsutism
advise weight loss if overweight
combined oral contraceptive pill
facial hirsutism: topical eflornithine - contraindicated in pregnancy and breast-feeding
Hyperhidrosis
Excessive sweating
topical aluminium chloride preparations are first-line. Main side effect is skin irritation
iontophoresis: particularly useful for patients with palmar, plantar and axillary hyperhidrosis
botulinum toxin: currently licensed for axillary symptoms
surgery: e.g. Endoscopic transthoracic sympathectomy. Patients should be made aware of the risk of compensatory sweating
Impetigo
a superficial bacterial skin infection usually caused by either Staphylcoccus aureus or Streptococcus pyogenes. It can be a primary infection or a complication of an existing skin condition such as eczema, scabies or insect bites (common in children)
‘golden’, crusted skin lesions typically found around the mouth
very contagious
Management;
conservative- children should be excluded from school until the lesions are crusted and healed or 48 hours after commencing antibiotic treatment
Localised- hydrogen peroxide 1% cream, topical fuscidic acid if unable
Severe- oral flucloxacillin (erythromycin)
Keloid scars
tumour-like lesions that arise from the connective tissue of a scar and extend beyond the dimensions of the original wound
Predisposing factors;
ethnicity: more common in people with dark skin
occur more commonly in young adults, rare in the elderly
common sites (in order of decreasing frequency): sternum, shoulder, neck, face, extensor surface of limbs, trunk
Treatment;
early keloids may be treated with intra-lesional steroids e.g. triamcinolone
excision is sometimes required
Keratocathoma
Keratoacanthoma is a benign epithelial tumour. They are more common with advancing age and rare in young people.
Features - said to look like a volcano or crater
initially a smooth dome-shaped papule
rapidly grows to become a crater centrally-filled with keratin
Spontaneous regression of keratoacanthoma within 3 months is common, often resulting in a scar. Such lesions should however be urgently excised as it is difficult clinically to exclude squamous cell carcinoma. Removal also may prevent scarring.
Ketoconazole
Due to the high risk of hepatic toxicity (ranging from hepatitis to cirrhosis/liver failure) it advised against the use of oral ketoconazole completely.
This does not affect the prescription of topical ketoconazole
Koebner phenomenon
The Koebner phenomenon describes skin lesions that appear at the site of injury. It is seen in:
psoriasis
vitiligo
warts
lichen planus
Leukoplakia
a premalignant condition which presents as white, hard spots on the mucous membranes of the mouth. It is more common in smokers.
Biopsies are usually performed to exclude alternative diagnoses such as squamous cell carcinoma and regular follow-up is required to exclude malignant transformation to squamous cell carcinoma, which occurs in around 1% of patients.
Lichen planus
itchy, papular rash most common on the palms, soles, genitalia and flexor surfaces of arms
rash often polygonal in shape, with a ‘white-lines’ pattern on the surface (Wickham’s striae)
Koebner phenomenon may be seen (new skin lesions appearing at the site of trauma)
oral involvement in around 50% of patients: typically a white-lace pattern on the buccal mucosa
nails: thinning of nail plate, longitudinal ridging
Planus (P’s)- purple, pruritic, papular, polygonal rash on flexor surfaces. Wickham’s striae over surface. Oral involvement common
Lichenoid drug eruptions - causes:
-gold
-quinine
-thiazides
Management of lichen planus
topical steroids
benzylamine mouthwash or spray is recommended for oral lichen planus
extensive lichen planus- oral steroids or immunosuppression
